Hollywood's greatest war heroes, from John Wayne to Sylvester Stallone, have been men who have elaborately avoided the world's real battlefields. So it is fitting that Mel Gibson, now the definitive cinematic nationalist, is a man of no great patriotism. When he starred in Braveheart, everyone knew he was not Scottish. Since Gibson is commonly believed to be Australian, his new American Revolution epic, The Patriot, would seem to be equally improbable.

As it happens, Mel Gibson was born in New York state and holds a US passport. But his wife and children are Australian, he has homes in both countries and a cynical approach to politics that undercuts the thunderous flag-waving message of a film that was released over the Fourth of July holiday in the States.

The Patriot has been hugely controversial: criticised for demonising the British Army, for white-washing the slave states and for indirectly contributing to Holocaust denial. A big, simplistic film, it shows the British burning down a church filled with people, while the all the black characters in the movie - set in slave-owning South Carolina - are free, well-fed, happy and grateful to the Mel Gibson character.

Unsurprisingly, but with some justification, Spike Lee has accused the film of racism. The US Ambassador to Britain, Philip Lader, joined the debate yesterday by refusing to defend the film and admitting 'the perpetuation of myths and the exaggeration of stories does not serve our countries well'. And the Lord Mayor of Liverpool has sprung to the defence of the historical model of the film's prisoner-murdering Colonel Tavington, placing a portrait of Banastre Tarleton in his office. The most extreme criticism has come from the New York Post's Jonathan Foreman, who argues that by suggesting that all armies commit gross atrocities, it makes the crimes of the Nazis seem par for the course.

All this is the kind of fuss that Gibson enjoys: he made Braveheart and the massively violent Payback anticipating that they would cause trouble. He won't, however, let his children see these films. He has some fervent beliefs, amongst them that John and Robert Kennedy were killed because they wanted the US out of Vietnam. But above all, there is his unshakable Catholicism: Gibson is opposed to birth control, abortion, divorce and the theory of evolution. In a business where marriages often last months, Gibson - married since 1980, seven children - has made himself a standard bearer of family values. By Hollywood standards he has a tiny entourage: he or his wife normally pick up the kids from school.

'There's nothing more important than your family,' he said recently. 'If you ruin that part of your life, what's left? Work? Money? Screwing around? I see a lot of people living like that who tell themselves they're having a good time but if you look under the surface you see lots of corpses masquerading as human beings.'

Not that Gibson has always been a model citizen. In the mid-Eighties he was drinking five beers before breakfast, and - like his cinematic heir, Russell Crowe - never shied away from a punch-up in a bar. There were often girls with him in those bars, although it was never proved that he broke the sacred marriage vows. He was arrested for drunk driving in 1984. In either 1986 or 1991 - depending on which story you believe - he managed to stop drinking completely. Smoking is another matter: he seems constantly on the verge of giving up.

Gibson is a sex symbol whose backside has famously been exposed in a number of films, but says he does not like sex scenes. 'It's uncomfortable, especially with cameras watching you.' When interviewed, he is either entertainingly flip or grumpy, but either way manages to keep his private life guarded. We know, however, that he likes to engage in traditionally 'manly' endeavours, like hunting and farming. 'There's a lot of anger and hostility under Mel's surface,' according to Lethal Weapon director Richard Donner. And as he has curbed his youthful rebelliousness, the example of his father - 'a very capable man' according to his son - looms larger.

Hutton Gibson, now 82, is the son of an Australian opera singer who moved to the US. He worked as a railway brakeman until an injury forced him to retire early, with a generous compensation package. Though he disapproved of television, he had a successful run as a quiz show contestant, picking up $21,000 on Jeopardy. In 1968, he moved his family - eventually 11 children, including one adopted - to Australia. He formed a group called the Alliance For Catholic Tradition, and has several polemics in print decrying the influence of Vatican II, including 'Is The Pope A Catholic?' and 'The Enemy Is Here'. He has described the burning of heretics as 'an act of charity', and contends that even the current Pope is disturbingly liberal.

At the time of the move to Australia, Mel, the sixth child, was 12. He went to an all-boys school but admits that he wasn't much of a student. He was considering becoming a journalist or a chef when his sister Mary sent in an application on his behalf to the National Institute of Dramatic Arts at University Of South Wales. He did not make it to graduation - 'an honourable discharge', he says - but it didn't matter. It had never been a better time to be an actor in Australia: led by directors Peter Weir and Phillip Noyce, the film industry had come alive. After appearing as a surfer in a movie called Summer City (1977), Gibson auditioned for a role in first time director George Miller's Mad Max (1979). His face had just been smashed up in a bar brawl, which probably helped him get the title role as a cop seeking revenge in a post-apocalyptic world.

The film made Gibson an instant star, and it turned into international stardom after the sequel - The Road Warrior - and Peter Weir's Gallipoli (both 1981). In 1980, he married Robyn Moore, a dental nurse. Little seen in public, she is widely considered to be the tougher half of the couple, and the one who held the family together as Gibson's drinking worsened following his arrival in Hollywood in the early Eighties. After Mad Max Beyond The Thunderdome (1985), Gibson dropped out of the business for two years, spending the time on his 800-acre Australian cattle ranch.

He returned as Riggs, the suicidal cop in Lethal Weapon (1987), which turned out to be the starting point of a series even more profitable than Mad Max. The first Lethal Weapon had the qualities that Gibson says he looks for in a film. 'I want the nightmare. I need that conflict, the edginess that makes you want to know what happens next.' What Gibson has certainly proved is that he has no fear of ridicule, surprising everyone by playing a macho but decently received Hamlet in Franco Zeffirelli's 1990 film.

In the Nineties he also started directing, with 1993's modest drama The Man Without A Face leading to the bombastic Braveheart (1995). 'I know I'm gonna get crucified,' he said before the release of his spectacularly bloody William Wallace biopic, but instead he was rewarded with both massive box office and Oscars for best director and best picture. Like many successful actors, he started up a production company, Icon. But whereas most actor's companies remain small-scale, Icon - Gibson is chairman - has grown, buying up other companies, setting up its own London-based European distribution arm and making films as far from Gibson's own territory as Kevin and Perry Go Large. It has also carried out the more traditional role of providing a home for Gibson's vanity projects, notably the badly received, Wim Wenders directed, Million Dollar Hotel, from an idea by Bono with Gibson as a mutant FBI agent. One of the film's stars, Peter Stormare, says of Gibson: 'That's the way you should do it. Take a garbage role for the money, like Lethal Weapon 4, and then do what you want to do. He's a cool fella.'

Although The Patriot has underperformed at the US box office, making Gibson's alleged record-setting $25 million fee look unwise, it is unlikely to damage him much. After all, he has had a double presence in the cinema this summer, also providing the voice of Rocky the Rooster in Chicken Run. And if things get rough again, he has his Australian ranch, his Connecticut mansion and his two houses in Malibu to retreat to.

However, he has had trouble with the Connecticut house: the neighbours are not happy with the two donkeys and six sheep he has been keeping on his land in a residential area. But despite the occasional flop, Gibson's career has been a remarkably smooth affair, and at 44, he is just coming into his prime as a Hollywood leading man. These days, he is the prototype for good-looking but rough-hewn antipodean stars like Crowe and Heath Ledger, who plays his son in The Patriot. 'He is more like a guy than any guy I have ever met,' claims screenwriter Robert Towne.

Perhaps Gibson's succinct account of his current state of mind explains why he has prospered. 'When I was younger, I was tortured. But then I decided it just wasn't worth spending my time on.'